In the e-mail, the microblogging company noted: "Twitter believes that your account may have been compromised by a Web site or service not associated with Twitter. We've reset your password to prevent others from accessing your account."

It remains unclear how many have been affected by the password reset e-mail or what's caused the mass e-mailing of its users.

A post by TweetSmarter on Wednesday noted that in some cases when "large numbers of Twitter accounts have been hijacked," the company sends out these e-mails en masse, even sending messages to accounts that may not have been affected by any hack or hijack to err on the side of caution.

So far, a few high profile accounts have noted interference, including David Mitchell, who said:

"Got an e-mail from Twitter telling me that my password had to be changed because they thought my account had been hacked," adding in another tweet: "So I've changed it, but the only evidence of hacking I can find is that my tweet about my Observer column last Sun has disappeared. Weird."

A Twitter spokesperson told CNET: "We're committed to keeping Twitter a safe and open community."

"As part of that commitment, in instances when we believe an account may have been compromised, we reset the password and send an e-mail letting the account owner know this has happened along with information about creating a new password. This is a routine part of our processes to protect our users."

However, the recently sent out password reset e-mails hit a wider scope of Twitter users than were initially intended, the Twitter spokesperson added.

"In this case, we unintentionally reset passwords of a larger number of accounts, beyond those that we believed to have been compromised. We apologize for any inconvenience or confusion this may have caused."